ASTM International

Standard Practice for Examination of Mill and Kiln Girth Gear Teeth — Electromagnetic Methods
 N E2905/E2905M

Annotation

This practice describes a two-part procedure for electromagnetic evaluation on gear teeth on mill and kiln gear drives and pinions. The first part of this practice details the ability to detect 100 % of surface-breaking discontinuities only in the addendum, dedendum, and root area on both the drive side and non-drive side of the gear tooth using an eddy current array. The second part of the examination is to size or measure accurately the length and depth of any cracks found in these areas using electromagnetic methods. No other practice addresses the use of electromagnetic methods for the detection and sizing of surface-breaking discontinuities on mill and kiln ring gear teeth.

This practice is used only for crack detection, alignment issues, wear patterns, and early signs of macro-pitting. It will not illustrate a full gear tooth analysis. Visual examination by an experienced gear technician is the only way to analyze fully gear teeth wear patterns and potential failure.

Two technicians, or one technician and a technical assistant, are typically required for this practice. One technical assistant guides the probe and the technician operates the computer/software and analyzes the gear teeth condition.

It is important that the appropriate method standards, such as Guide E709 and Practice E2261, if the alternating current field measurement approach is used for crack sizing, accompany the technician when performing the examination.

It is recommended that the technician reviews the appendixes in this practice in advance of starting the job.

A clean gear is recommended for a complete gear analysis. Depending on the lubrication used, the technician, in discussion with the client, shall determine the appropriate cleaning procedure, if cleaning is required. If an oil bath lubrication system is used, ensure the gear teeth surface is clean. If an asphaltic-based or synthetic-based lubricant is used, refer to the annexes and appendices in this practice.